It is the long range objective of this project to study the neural organization underlying visual perception in primates. The topics of present interest are: a) chromatic, temporal and spatial properties of neurones of the retina, lateral geniculate nucleus, primary visual cortex and extra-striate cortex, b) how this information is processed along these centers, and c) how these single cell data are related to psychophysical results in humans. BIBLIOGRAPHIC REFERENCES: de Monasterio, F.M., Gouras, P., and Tolhurst, D.J.: Spatial summation, response pattern and conduction velocity of ganglion cells of the rhesus monkey retina. Vision Res. 16: 674-678, 1976. Zrenner, E.: Color opponency in visually evoked cortical potentials (VECP) in man. ARVO Abstracts, p. 157, suppl. to Invest. Ophthalmol. 1977.